My internet connection is OK beccause if I disconnect the cable from the vportal and connect it to the pc it works.I dont have access to the modem because is a buildingInternet connection doesnt need identification you just connect the cable!

Likely your school is blocking the outbound ports to connect to Vonage. Your standard web traffic that is working is running over 80 or 443. It could also be that they're using a web proxy. Do you have to logon to your campus computer with a userid and password?